mom.math.is_prime

[rubik]

is_prime returns True for 1. You should fix that.

Thanks,
rubik

[gorakhargosh]

Heh. Yep. Haven't tested that routine yet.
Soon soon. =)

Cheers.

[rubik]

Ok. Are you planning to add tests?

[gorakhargosh]

Yep. Only 4 modules in the library don't have tests yet.
The rest already have 100% coverage.

mom/init 6 0 0 100%
mom/codec/init 59 0 0 100%
mom/functional 83 0 0 100%
mom/security/init 3 0 0 100%
mom/security/codec/init 21 0 0 100%
mom/security/codec/asn1/init 3 0 0 100%
mom/security/codec/asn1/rsadsa 15 0 0 100%
mom/security/codec/asn1/x509 39 0 0 100%
mom/security/codec/pem/init 38 0 0 100%
mom/security/hash 30 0 0 100%
mom/builtins 108 2 0 98%
mom/security/codec/pem/rsa 66 8 0 88%
mom/security/codec/pem/x509 48 6 0 88%
mom/security/random 60 15 0 75%
mom/_builtins 24 9 0 63%
mom/decorators 10 4 0 60%
mom/codec/json 34 18 0 47%

^ 100% coverage. Ignore the stats shown. They're because of compatibility
imports.

Pending:
mom/math 122 93 0 24%
mom/_types/init 3 3 0 0%
mom/_types/bytearray 49 49 0 0%
mom/itertools 102 102 0 0%
mom/security/rsa/init 26 26 0 0%
mom/security/rsa/keys 43 43 0 0%
mom/security/rsa/pycrypto 32 32 0 0%

So, yep. Writing tests right now. =)

[rubik]

Ok! :)
I have noticed that sometimes mom.math.make_prime_sieve gives wrong results:

In [2]: filter(lambda n: not mom.math.is_prime(n), mom.math.make_prime_sieve(10))
Out[2]: [9]
In [3]: filter(lambda n: not mom.math.is_prime(n), mom.math.make_prime_sieve(100))
Out[3]: []
In [4]: filter(lambda n: not mom.math.is_prime(n), mom.math.make_prime_sieve(1000))
Out[4]: [961]
In [5]: filter(lambda n: not mom.math.is_prime(n), mom.math.make_prime_sieve(10000))
Out[5]: []

[gorakhargosh]

You're welcome to rewrite the routine.
This one comes from tlslite. I've rewritten
almost everything I've imported from scratch
because of these problems. tlslite doesn't have
a battery of tests, so... =)

[rubik]

Oh no, it wouldn't be fast enough! On stackoverflow I saw an optimized sieve, I only have to find it.

EDIT: Here it is!

def rwh_primes1(n):
    # http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n-in-python/3035188#3035188
    """ Returns  a list of primes < n """
    sieve = [True] * (n/2)
    for i in xrange(3,int(n**0.5)+1,2):
        if sieve[i/2]:
            sieve[i*i/2::i] = [False] * ((n-i*i-1)/(2*i)+1)
    return [2] + [2*i+1 for i in xrange(1,n/2) if sieve[i]]

It comes from this discussion: http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n-in-pythonù
It is very fast: it can compute primes up to 10 million within a second! And it uses half the list!

[gorakhargosh]

Awesome!

[rubik]

Yes it is! :)